Say you drink 2 cups of coffee every day. Is there any time T where there is zero coffee in the organism? If the answer is there is no Tm then is there an N=n

Say you drink 2 cups of coffee every day. Is there any time T where there is zero coffee in the organism? If the answer is there is no Tm then is there an N=number of days, where there are dangerous levels of coffee accumulated in the organism? or are we more in an equilibrium state?